1. Field of the Invention
The invention relates to electrostatic spray guns.
2. Description of the Prior Art
Many patents have been published on such guns, and further our previous patent application Ser. No. 9101812.7 (now PCT GB 92/00156 filed 25th Jan. 1992) relates to them. In our prior spray guns, however, the electrical forces have been applied to the fluid to be sprayed after its emergence from a container.
In current work, we have found the fluid may itself be part of the electrical path. Suitable fluids such as paints then appear to behave as if charged electrostatically, leading to generation of a cloud of separated charged droplets as soon as the paint issues from a nozzle. Then, with a suitably earthed target, the droplets are attracted and discharged electrically, to form a coating.